With over 635,000 inhabitants, Glasgow is the largest city in Scotland, ahead of Edinburgh, and the third largest city in the United Kingdom after London and Birmingham.

Around 80 AD, the Romans colonised the city, which was probably called Cathures at the time. The Romans later built the Antonine Wall around 140 AD to separate Roman Britain from Celtic and Pictish Caledonia. According to legend, Glasgow itself was founded by the Christian missionary St Mungo in the 6th century. He is said to have built a church on the site of today's cathedral. Construction of St Mungo's Cathedral began in the 12th century. In 1451, the University of Glasgow was founded by papal decree. By the beginning of the 16th century, Glasgow had become an important religious and academic centre.

In the 6th century Saint Mungo is said to have brought the body St Fergus, for burial. Saint Ninian is reputed to have dedicated the burial ground. Mungo built a monastic cell in the burial ground, and was buried in his church there in 614. His shrine in the Lower Church of Glasgow Cathedral was an important place of pilgrimage in the medieval period.

The first stone cathedral was built, initiated by the decision of David I to establish a bishopric at Glasgow, the new cathedral was consecrated in 1136. The cathedral rose slowly over a period of some 150 years.

Destroyed or severely damaged by fire, the first cathedral was succeeded by the present Gothic cathedral, which was consecrated in 1197. It was constructed between the 13th and 15th centuries. The church was the seat of the bishops and later the archbishops of Glasgow. Since 1690, the cathedral has no longer been the seat of a bishop. Since then, the designation as a cathedral has been a historical title of honour and indicates the original function as a Roman Catholic diocesan church of the Archbishopric of Glasgow.

Carved graffiti at the nave